The Diffraction of Multidirectional Random Waves by Rectangular Submarine Pits

2004 ◽  
Vol 126 (1) ◽  
pp. 9-15 ◽  
Author(s):  
Hong Sik Lee ◽  
A. Neil Williams
Keyword(s):  
Water Wave ◽  
Wave Theory ◽  
Boundary Integral ◽  
Integral Approach ◽  
Two Dimensional ◽  
Random Waves ◽  
Discrete Form ◽  
Random Surface ◽  
Directional Spectrum ◽  
Dimensional Boundary

The diffraction of multidirectional random surface waves with one or more rectangular submarine pits is investigated theoretically. The incident wave conditions are specified using a discrete form of the Mitsuyasu directional spectrum. The numerical model involves the superposition of regular-wave diffraction solutions based on linearized shallow water wave theory obtained by a two-dimensional boundary integral approach for water of uniform depth. Numerical results are presented for multi-directional random waves that illustrate the effect of the various wave and pit parameters on the diffraction characteristics of typical single and multiple pit systems.

The Diffraction of Multidirectional Random Waves by Rectangular Submarine Pits

2002 ◽  
Author(s):  
Hong Sik Lee ◽  
A. Neil Williams
Keyword(s):  
Boundary Integral ◽  
Integral Approach ◽  
Two Dimensional ◽  
Regular Wave ◽  
Random Waves ◽  
Shallow Water Theory ◽  
Discrete Form ◽  
Random Surface ◽  
Directional Spectrum ◽  
Dimensional Boundary

The diffraction of multidirectional random surface waves with one or more rectangular submarine pits is investigated theoretically. The incident wave conditions are specified using a discrete form of the Mitsuyasu directional spectrum. The numerical model involves the superposition of regular-wave diffraction solutions based on linearized shallow water theory obtained by a two-dimensional boundary integral approach for water of uniform depth. Numerical results are presented for multi-directional random waves that illustrate the effect of the various wave and pit parameters on the diffraction characteristics of typical single and multiple pit systems.

The Diffraction of Multidirectional Random Waves by Trapezoidal Submarine Pits

2003 ◽  
Author(s):  
Hong Sik Lee ◽  
A. Neil Williams ◽  
Sung Duk Kim
Keyword(s):  
Numerical Model ◽  
Wave Diffraction ◽  
Boundary Integral ◽  
Random Wave ◽  
Linear Wave ◽  
Wave System ◽  
Random Waves ◽  
Random Surface ◽  
Directional Spectrum ◽  
Integral Equation Approach

A numerical model is presented to predict the interaction of multidirectional random surface waves with one or more trapezoidal submarine pits. In the present formulation, each pit may have a different side slope, while the four side slopes at the interior edge of any given pit are assumed equal. The water depth in the fluid region exterior to the pits is taken to be uniform, and the solution method for a random wave system involves the superposition of linear-wave diffraction solutions based on a two-dimensional boundary integral equation approach. The incident wave conditions are specified using a discrete form of the Mitsuyasu directional spectrum. The results of the present numerical model have been compared with those of previous theoretical studies for regular and random wave diffraction by single or multiple rectangular pits. Reasonable agreement was obtained in all cases. Based on these comparisons it is concluded that the present numerical model is an accurate and efficient tool to predict the wave field around multiple submarine pits of trapezoidal section in many practical situations.

A Three-Dimensional Modeling of Multidirectional Random Wave Interactions by Multiple Rectangular Submarine Pits

2004 ◽  
Author(s):  
Hong Sik Lee ◽  
A. Neil Williams ◽  
Sung Duk Kim
Keyword(s):  
Numerical Model ◽  
Velocity Potential ◽  
Three Dimensional ◽  
Boundary Integral ◽  
Integral Approach ◽  
Random Wave ◽  
Random Surface ◽  
Directional Spectrum ◽  
Practical Applications ◽  
Three Dimensional Modeling

A three-dimensional numerical model is presented to predict the interactions of multidirectional random surface waves with one or more rectangular submarine pits. The water depth in the fluid region exterior to the pits is taken to be uniform. The three-dimensional Green function in the boundary integral equation, obtained by Green’s second identity, has been used for the solution of the velocity potential and its derivative in fluid interface between regions, and also a form of the Fourier expansion is utilized for the solution of the velocity potential in the interior region. The incident wave conditions are specified using a discrete form of the Mitsuyasu directional spectrum. The present method is based on the cumulative superposition of linear diffraction solutions obtained by a three-dimensional boundary integral approach. The results of the present model have been compared with those of previous theoretical studies for both regular and random wave diffraction by single or multiple pits. Reasonable agreement was consistently obtained in all cases. In accordance with good agreement from these comparisons, it is concluded that the present numerical model may accurately be utilized to predict the three-dimensional wave field around multiple submarine pits or navigation channels in many practical applications.

A note on the total reflexion or transmission of surface waves in the presence of parallel obstacles

1975 ◽  
Vol 67 (3) ◽  
pp. 465-472 ◽  
Author(s):  
D. V. Evans
Keyword(s):  
Surface Wave ◽  
Surface Waves ◽  
Water Wave ◽  
Wave Theory ◽  
Two Dimensional ◽  
Total Transmission ◽  
Vertical Barriers ◽  
Total Reflexion ◽  
Dimensional Surface

It is shown how a two-dimensional surface wave can be either totally reflected or totally transmitted in the presence of two parallel vertical barriers each containing a small gap. Total transmission of a surface wave past obstacles has been known to occur in many situations in water-wave theory, but total reflexion is a comparatively new phenomenon which could be of practical use in the design of breakwaters.

scholarly journals METHOD OF ANALYSES FOR TWO-DIMENSIONAL WATER WAVE PROBLEMS

1976 ◽  
Vol 1 (15) ◽  
pp. 155 ◽  
Author(s):  
Takeshi Ijima ◽  
Chung Ren Chou ◽  
Akinori Yoshida
Keyword(s):  
Green’S Function ◽  
Boundary Value Problems ◽  
Green's Function ◽  
Water Wave ◽  
Boundary Value ◽  
Wave Transformation ◽  
Two Dimensional ◽  
Simple Method ◽  
Dimensional Boundary ◽  
Horizontal Cylinders

One of the most powerful tools to analyze the boundary-value problems in water wave motion is the Green's function. However, to derive the Green's function which satisfies the imposed boundary conditions is sometimes difficult or impossible, especially in variable water depth. In this paper, a simple method of numerical analyses for two-dimensional boundary-value problems of small amplitude waves is proposed, and the wave transformation by fixed horizontal cylinders as an example of fixed boundaries, the wave transformation by and the motion of a cylinder floating on water surface as example of oscillating boundaries and the wave transformation by permeable seawall and breakwater as example of permeable boundaries are calculated and compared with experimental results.

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